Mechanical vernier



April 1, 1924 www@ E. E. L. BOYER ET Al..

MECHANICAL VERNIER Original File@ July 22a., 1915 lI I? Patented Apr, l,i924.,

UNITED sTATEs PATENT oEEicE;9

EDITH E. L. BOYER AND FREDERICK G. L. BOYER, OF DAYTON, OHIO,kASSCIIGNORS, BY

IVIESNS ASSGBUVIENTS, TDAYTON SCALE COMPANY, 0F DAYTON, OHIO TION CE'NEV JERSEY.

MECHANICAL VERNIER.

Original application tiled July 24, 1915, Serial No. 41,667. Divided andthis application 1920. Serial No. 372,792

To all whom t 'may concerti:

Be it known that we, EDITH E. L. BOYER and Fnnnnarcn G. L. BOYER,residing at Dayton, in the county of Montgomery and ccitate of Ohio,have invented anew and usefuly Mechanical Vernier, of which thefollowing is a specification.

@ur inventionv relates toany type of computing or measuring deviceinwhich the relative movement of two members, or their relative positionas compared to a certain standard or zero position, is measured in anyunits of measurement designed to be expressed in figures representingunits and figures "representing higher denominations such as:millimeters, centimeters, etc.; fractions of inches, inches, etc.;minutes, and degrees oi' arc; cents, dimes, and dollars, pence,shillings, and pounds; ounces and pounds; minutes `and hours of time; orthe like.` Throughout this specification the word unit is used todesignate the smallest unit ol measurement which it is desired toexpress, the fractions thereof being disregard ed except as they help todetermine what vthe units figure should be.

The present application is a division from our application filed July24, 1915, Serial No.' 41,667 now ?atent No. 1,338,282, April 27,1920.

The object of our invention yis like that ci? the ordinary vernier, tomaire possible the accurate determination of units of relative movementthat are'too small to be determined directly with convenience. A'further object or our invention is to facilitate rea-ding or recordingthe value of said relative movement, to prevent mist-altes, and toma-irefamiliarity with a vernier unnecessary for determining the reading. Thisis done by providing mechanism which will automatically determine thenumerical value oi the relative movement of the two members i. e. thereading which would be given by the equivalent Vernier.

in order to prevent mistakes in reading or recording thevalue'of saidrelative movenient. the mechanism is so arranged that it will set uprthe figures representing the aforesaid numerical value on type wheelsfor printing or on visual indicatorsor both, in such manner that nofigures are in a `mee April 1o,

position for reading or printing except those actually needed torepresent the correct reading. Il the individual readings are notdesired it is not necessary to provide said indicating or yprintingmeans but instead the mechanism may be connected directly to ato-talizer, which would indicate tions on the scale; and (on the otherof the y two relatively movable members) a series of pawls for thegraduations on the Vernier. When the relative motion between the twomembers ceases'we press the series of pawls against the notched memberallowing pawls to enter notches with which they register. The pawl whichenters a notch is so ranged as to arrest the movement of the memberwhich represents the units ligure in the reading, is such a position asto eX- pose the correct units ligure at the point where the readingistaken. (This point will hereinafter be called they reading point.) Thefigures of higher denominal tion are taken directly from the relativeposition of the two members, just as is the case in anordinary Vernier,but their determination is controlled by the pawl which determines theunits figure.

rIhe mechanism and its operation will be more easily understood byreference to the` accompanying drawings in which:

Fig. l. 1s a front view of our vernici' showing the notched member andpawls in a position indicating a reading of one unit.'

Fig. 2 is a sectional view of the same showing also the numeral bearingwheels, connected thereto, on which the reading is indicated.

Fig. 3 is an enlarged view showing a portion ofthe notched disk shown inFigs. l and 2, together with parts oi the pawls in the positions whichthey occupy when A CCR PORA- of the views.

the reading is halfway between two units. Fig. 4 is a detail View of thetens and units Wheels, with part of the tens wheel Vbroken away to showthe internal construction, and of the justifying mechanismvprior to itsoperation Vand after the operation of the Yunits wheel to a positionindicating nine units.

Fig. 5 shows the same after the justifying operation has taken place,and shows inV addition certain parts attached to the tens wheel and partof the transfer mechanism not shown in Fig. 4. Y

Fig. 6 is a perspective View of the'pilot pawl used in connection withthe j ustifying mechanism. i

Fig. 7 is a diagrammatic View oi: the mechanical Vernier, withmodifications adapting it to measure rectilinearinstead "of ro` tarymotion. 1

Fig. 8 shows the same device with the Zero pawl located to Vcorrespondmore closely with the common Vernier inthe lower part of the ligure, andwith the relative position of the two members representing a movement of40% units from zero position.

Fig. 9 is an end View of the parts shown in Figs. 7 and 8. j

Similar numerals referto like parts in all The arrangement of ourinvention illustrated in Figs. 7 VVand 8, where it corresponds to thesimplest 'form ofV Vernier-a rectilinear, direct, decimal Vernier-showsthe analogy most clearly and exhibits the principles of our inventionmost simply, and will iirst be described.

In Fie. 7 we have a bar or scale 120 which we will for the presentconsider as movable, the directionof movement shown by the arrow beingconsidered as positive. Vlts movement is measured in units in thedecimalY system. Along the lower edge of this bar is a series ofgraduations 121 numbered O, 10, 20, etc. Each of Vthe spaces betweenthese graduations represents ten units of movement.V On the upper sideof said bar or scale 120 is a series of notches 122. YThe right handedges or-.corners 123V of these notches Vare cut so as toycorrespendexactly with ti e Vgraduations 121. Just below bar' 120 is aVernier 140, which we will for the present consider as stationary, andwhich carries a series of graduations 141. In this decimal Vernier thereare ten ofthese graduations numbered vfrom O to 9, and since it is adirect Vernier ten spaces on the Vernier are exactly equal to ninespaces on the scale 120, as may be readiiy seen by referring to Fig. 7.(It it were a retrograde Vernier ten spaces thereon would exactly equaleleven spaces on scale 120.) ThusV one Vunit of movement of bar-12()will bring a graduation thereon opposite the f one graduation en Vernier140,two units of movement will bring a graduation on bar 120 oppositethe two graduationon Vernier 140, and so on. Ten units of movement willbring the tenth graduation on bar 120'opposite the Zero graduation onVernier 140, just as the zero graduation is seen in' Fig. 7, and thenone, two, three, etc. unitsV of further movement will again bring agraduation on bar 120 op-V posite lthe 1, 2, 3, etc., graduation onVernier 140. The units figure in the Vernier reading-which readingrepresents the numerical value oi' the relative movement between bar12() and Vernier 140 Vis thus determined by the graduation on Vernier140 which is most nearly opposite graduation on scale 120, and the tensgure and iigures of higher denomination inthe reading are read from thefirst graduation on scale 120 to the right of the Zero graduation onVernier 140. Thus in Fig. 8 the units Value is'seen to be between Zeroand one, andthe tens is seen to be four, making the whole reading 403;which, according to usual practice is called 41. So far we have simplydescribed an ordinary Vernier and the method in which the reading isdetermined. l/Ve shall now show how, in our device, we determine thesame reading mechanically by substituting mechanical elements for thegraduations on the Vernier and scale, Vand providing mechanism for theiroperation.

Just above the bar 120 is mounted a stationary series of transverselyslidable pawls 142, of which the right hand sides orcorners 143 arelocated so as to correspond exactly with the graduations 141 on Vernier140,

f as indicated at graduation 4 in Fig. 7. The

only difference between, the arrangements shown in Figs. 7 and 8 is inthe location of the zero pawl. A little consideration will show thisdifference to be of no importance except as it may aect the practicalconsiderations in the design of connected parts.

By inspection of Fig. 7 it is seen that the Vernier' reading is Zerovand the zero pawl registers with a notch in bar 120. It will further beseen that by movingbar 120 one, two, three,` etc., units of movement theVernier reading will be one, two, three, etc., units, and the one, two,three, etc., pawl will register with a notch in bar 120. Then todetermine the Vernier reading by means of our invention it is simplynecessary to yieldingly press the series oi -pawls 142 against thenotched bar 120 in such a manner that the pawl -which registers with anotch will enter the notch while the others will be arrested by the topsurface of the bar 120. After this is done the iinger 160 is moved fromthe positionv shown, in the direction indicated by the arrow, until itsmovement is arrested by the pawl which has entered a notch.v The way inwhich this occurs will be apparent from Fig. 9 in which the dotted linesindicate the position of one of the pawls 142 which has entered a notch,showing how `it then obstructs the path of the finger 160. Thepositionin which this finger 160 is arrested controls the indication ofthe units ligure in the reading as will be explained later.

,It will be noticed that in Figs. 7i and 8 thev notches 122 are the sameWidth as the pawlsV 142 and that unless the movement yot the bar can beexactly divided by the unit of measurement none of the pawls 142 willeX- actly register with anyof the notches122, and that none of them willenter notches when pressed against the bar 120. In order to provide forthe arrest of finger 160, in whatever position the bar 120 may be,l wecut away the sides of the notches 122 as shown by dotted lines in Figs.7 and 8,` so that it will always be possible for at least one pawl toenter a notch. y

The common practice is to neglect fractions (of the smallest unit inwhich measurement is desired) which are less than one half unit, andwhen the fraction is equal to one half unit or more tov count it as afull unit. To make the reading given by our device conform to this4practice we cut away the sides of the notches122 in the followingmanner, referring to Fig. 8 in which the bar 120 has moved just one halfunit beyond the position representing exactly 40 units: At this pointthe reading should change from O units to 1 unit. It the bar 120 hadstopped with the 40 graduation exactly opposite the zero graduation onVernier the right hand side 143 of zero pawl ,142 would register exactlywith the right hand side 123 of the 40 notch 122, and since the pawl andnotch are of the same width their left hand sides would also registerexactly. At all points between this position and that shown in Fig. 8the unit reading should be zero, andconsequently the zero pawl shouldenter the notch. To make this possible the` left hand side of the notchis cut away an amount equal to one half unit of movement, as shown byvthevdotted line. At the position shown infFig. 8 the unit reading shouldchange from zero to one, and consequently the one pawl should enter anotch. To make this possible the notch opposite the one pawl must haveits right side cut away an amount equal to exactly one half unit,asshown by the dotted line. It will now be noticed that the readingfinger moves past the pawls indescending sequence so that when it isarrested by the one pawl it is immaterial whether or not the zero pawlis also .in a notch. This fact makes it possible to cut away the leftside of the notch slightly more than one half unit in order to beperfectly sure that in practice the zeroy pawl will continue `tofunction until the one pawl begins to function. Continuing the samereasoning, we see that all notches needito be cut away an amount equalto exactly one halt unit on the right hand side and an amount equal toone half unit plus clearance on the left hand side. This insures atleast one pawl being in a position to arrest linger 1GO no matter Iwhatthe position of bar 120 may be.

If it is desired that the transition point between the consecutive unitreadings be at some point other than haiic way between the Whole unitswe simply out away the right and the right hand side 123 of the notchwhich is opposite the zero pawl when the bar 120 1s in its zeropositionjA the width and spacing of notches being the same in Vany case.

Throughout the remainder of the description we will consider the sidesof the notches cut away as described so that the transition pointbetween two consecutive units in the reading comes midwaybetween then'i.lt will be noted that for a shortkdistance on one side of `thistransition point two pawls may occupy notches simifiltaneously, while onthe other side of said transition point only one pawl can occupy anotch.

From the foregoing description it will be 4' seen that the reading iscontrolledby the forward sides or corners 123 oiI notches 122 and thecorresponding sides or corners 143 Y of pawls142, which will hereinafterbe called the active or controlling edges or corners, the locations' ofthe'other sides of pawls and notches being merely a result ot practicalconsiderations olf It wilt also be noticed that the active corners otthe notches are the parts or elements of the mechanism which are spacedlike the graduations on a scale, and the active cor-y ners of the pawlsare the parts or elements of the mechanism which are spaced like therThroughout this u graduations on a vernier. specication when the spacebetween pawls or notches is mentioned it will be understood as referringto the space between the active edges or corners.

yBearing in mind the principles of our inl vention as described, themodifications involved in the embodiment thereoiC illustrated in Figs. 1to 6 inclusive will be readily understood. The principal difference isthat in this case our invention is adapted to measure rotary instead ofrectilinearnmtion.

In Figs. 1, 2, and 3V the notched disk 20 1s the equivalent of the baror scale 120 in Figs. 7 and 8 and like it will for the present pawls 42correspond to pawls 142 and their.

Y rockV on Vstuds 46.

beconsidered as the movable member whose movement is to be measured inunits in the decimal system. ThisV disk carries a series of notches 22with theactive edges or corners 23 corresponding to thel notches 122 andcorners 123 in Figs. 7 and 8. Vernier' 47 whichV are attached to pins 48in al rock-Y ing ring 50 mounted on frame 45, concenf ltric with disk20, and boss 44. When disk 2O is to be rotated, the pawls42 are re`moved from contact therewith by rocking the ring 50 in acounter-clockwise direction', thus releasing the tension on springs 47and bringing ,pins 49 in ring .5G int-o contact with pawls 42rockingtheni on studs 46 until lthey are out of contact with disk 20.

The finger 60 which is rigidly attached to Y `shaft 61 corresponds tothe iinger 160 in Figs. 7 and 8. This finger normallystands, in Fig. 1,between the zero and one pawls as shown by the dottedV line; androtates'in a clockwise direction, passing the pawls in descendingsequence, until arrested bythe pawl which has entered a notch. Fig. 1shows the finger 60 as it has been arrested by the one pawl.

That the transition point Vbetween consecutive unit readings iscontrolled as already described will be apparent Yfrom Fig. 3. lf,however, (see Fig. 1) the Zero and one pawls simultaneously occupynotches the zero pawl would arrest the finger 60 vwhich, 'in that case,should have been arrested by the one pawl. This slightly erroneousresultit never occurs except at the transition point between Zerov andone units, and never amounts to moreA than a very small fraction of aunit--is prevented by the arm on the zero pawl and the link 56 pivotedto the one pawl and sliding on pin 57 in theboss 44 on frame The pin 49which lifts the one pawl off of disk 2O is set so as to allow the onepawl toi dro into notch before the other pawls have been dropped ontodisk 20. This action of the one pawl throws link 56 intorthe path of arm55 on the zero pawl and prevents thel entrance of that pawl into anotch, `thus permitting the finger 60 to pass 'thezero pawl and bearrested by the one pawl. 'If

the one'pawl is arrested bythe surfaceA of disk20 and link 56 will notinterfere with the operation ofthe ZeroV pawl. Thus whenever two pawlsare ina position to simultaneously Voccupy notches-'the higher of theYtwo possible readings is always secured.

It will be noted.I that it is not essential thatV the fingerv 60 standVnormally between theYV Zero and one p'awls, as any other position' maybe chosen to simplify the problems of design. 56 and connections beplaced'between the Vsame twoV pawls as'the positionV chosen for thefinger 60, and that the finger 60 rotate in the sameV direction.l Even areversal inY` direction wouldbe possible if the` functionV of link 56were Vreversed and the opposite corners ofpawls and notches were locatedso as to be the determining factors in the reading.V I p Y p Aconnectionvanalogous to link 5,6 may be placedib'etween the `zeroI andone pawls in Fig. 7 andv betweenfthe zero andlnine pawls in Fig. 8 whereit will perform 'the same function as in Fig. 1.

It is only necessary that the link If the disk 2() carried only tenofthe Y notches 22'this forni of Vernier would measure one hundredthparts of a revolution and would be exactly equivalent' to' the one'shown in Figs. 7 and 8 Vif Vthe latter were formed into a circle. notedthat the disk 20carries twentyY notches andtheunits of measurement inthis vernier are therefore each equal to one two-hundredth part Vof arevolution fof 'the disk. The 'Ydisk20 might 'be provided with 30, 40,50,'.or more-.equally spaced notches to increase the number of units ofmeasurement to 300, 400,500, or moreper revolution .of

However, it will be j the disk.V VVith20, 30, 40, or .50' notches in thedisktheten Vernier pawls would `be located within the space of 'onehalf, one third,

one fourth, or one'fiftliofa circle if they were' spaced likept'l'iosein Figs. 7 and 8. Thisfwould 'not be a Vconvenient arrangement in thecase illustrated for sveeral rea-V sons, especiallyif the'number ofpawls were 30, 40, or more, as it would require the pawlsu to be spacedtoo close together' and would n seriouslyV decrease the movement per`unit of the linger 60 and the shaftil.

To avoidthese difficultiesv the space between adjacent' pawlsin theseries, in Fig. 1, is made 19/10 of the space between adjacent notches,instead of 9/10ias in Figs. 7 and 8. 'If there were 30, 40, or 50notches around the disk 20 the spacing of the'pawls Vwould be 29/10,39/10, or 49/1'0 respectively of the distance betweenV adjacent, notchesin the disk 20. Although'not common, verniers graduated inY a mannersimilar to this have occasionallyV beenV used on some instruments. On alittle consideration it will be apparent Vthat this change in the usualvernier.

spacing willl not affect theresults obtained,

Vfor the determining factor is the pawl that enters a notch, the notchthat it enters bcing immaterial.Y The essential feature of the spacingis the number of units' remain'- lit) ing in the space betweenconsecutive pawls after the largest possible multiple of the spacebetween consecutive notches has been subtracted therefrom. rlhus it willbe seen that, though iU is convenient, it is not necessary that thespaces between the pawls in the series be uniform.`

It is evident that the same principle of ,spacin the pawls can be usedin the recti.- linear verniers shown in Figs. 7 and 8 if it is kdesiufedto make the units oi measure# ment so small that the pa'wls would bespaced too close together when spaced as shown in those figures. it willbe noticed that when the uniformly spaced series of Vpawls used in therectilinear vernier are formed into a circular series kas shown in Fig.1 the space remaining whe-re the pawls on opposite ends of the seriesbecome adjacent is not equal to the uniform spaces between adjacentpawls within thek series.

Such a space is shown between the zero and one pawls in Fig. 1 where itis equal to 2.9/10 or the space between consecutive notches insteadofv19/10.

Having described the action or" our vernier in determining the unitsfigure in the numerical value of the relative movement of 'two members,we will now describe the method by whichthe figures representing thecomplete reading are brought into alignmentat the reading point, and theway in 'which the selection of the figures of higher denomination iscontrolled by the units iigure as determined by our'vernie'r.

In Fig. 2 it is seen that the shaft 61, to which finger is rigidlyfastened, carries a numeral bearing wheel 62', at its opposite end. Thenumerals thereon are so arranged that when finger 60 is arrested by'oneof the pawls d2 the corresponding numeral on wheel 62 will be exposed atthe reading point. In Figs.v l and 2 this numeral is seen to be 1.

ln Fig. 2 it will also bessen thatV the notched disk 2O is rigidlyattached to a tube or sleeve 24, which surrounds and forms a bearing forshaft 61, and carries at its opposite end a numeral bearing wheel 25,contiguous to the units wheel 62. rlhe numerals on the wheel 25represent tens and there will obviously be as manyv of these as thereare notches in disk 20. In the arrangement shown there are two completesets of numerals around the ivheel-twenty in all. rlhis Wheel turns withdisk 2O and measures its movement directly. The method by which theproper numeral thereon is brought into alignment at thereading pointwill be described presently. I

'it will be noted that, attached to the side oit Wheel 25, there istransfer gear 27 (see also with two teeth 29 (one 'for each series oi"numerals on wheel 25) which cooperater with a star Vwheel 75 and pinion76 mounted on shaft 77 to turn wheel 70 by means o ,t gear 71 attachedthereto. Nheel carries numerals representing hundreds. This mechanism isso arranged that each time the movement of wheel 25 indicates a changein the value of the hundreds figure one of the teeth 29 on the transfergear 27 passes star wheel and turns wheel 70 to expose a diiierent gureto represent hundreds in the reading. Y

In the device illustrated the whole capacity is not desired to begreater than 1,999

(ten revolutions of disk 20) and a series ofk numbers from 0 to 19 onthe hundreds wheel is suliicient for the purpose. if a higher capacitywere desired it would simply be necessary to number the hundreds wheellike the tens wheel 25 and provide it with a transfer gear like 27 totransfer to a thousands wheel. In this manner the capacity can beincreased indefinitely.

It is evident that unless the movement of sleeve 24: and disk 2Oamounted to exactly 19, 20, 30, etc., units the figures on wheel25 wouldnot be in alignment at the reading point ifthe wheel 25 were rigidlyattached to sleeve 2li and disk 20. In fact, in some instances thecorrect figure wouldv be so far out of alignment as to make italmostimpossible to tell which the! correct figure might be. To preventthis and to bring the correct numeral on wheel 25 into proper positionweprovide what we call justifying mechanism because its function issomewhat analogous to what printers call justifying. This 'mechanismimparts a forward movement to vwheel 257 (and kwhen necessary throughthe transfer mechanism to the hundreds wheel 70) suiicient toy bring thecorrect numeral into position.

In order lthatfthis Jorward movement take place the wheel 25 is looselymounted on thesleeve 2a` and is normally located so that when sleeve 24and disk 20 are in zero position, Vthe figure 9 on wheel 25 is readingposition, and when said sleeve and disk are in a position representingany number of even tens of units of movement the figure in readingposition is one less than the required figure. At such a time thejustifying mechanism must impart forwardmovement to the wheel 25 yequalto teu units of movement of disk 20. (It should be noted here that thefigures on wheel 25 andthe notches on disk 2O are ten units ofmovementapart.) lVhen sleeve 2e and disk 20 are in a positionrepresenting a certain number of odd units in addition to the even tens.the justifying mechanism is only required to move vwheel 25 an amountequivalent' to the dierence between said number of odd units and tenunits of movement of disk 20. y

For example, if sleeve 2li and disk 20 are in a positionrepresentingLi() units the iigure 3 on tens wheel 25 would be exposed at the j theunitsiigure from` 9 to -.O,and the .tens

Y reading point, and the justifying mechanism would bek requiredto-.move Vthe wheel 25 forward` vten units of movement to bring Vthetens `figure 4 into position. If sleeve 24 and disk have been brought toa position representing 44 units they havey carried thc tens wheel fourunit-sof movement beyond the figure 3 or 4/10 ofthe distance from 3 to 4and the justifying mechanism is only required to move it forward sixunits of movement in order to bring the tens figure 4 intoV position. Ifsleevel 24 and disk A20 are in a position representing I49 unitstheyhave senting 49gA `units the Zero, vernier `paw-l 42.

wouldj ust entera notch indisk V2O changing figure shouldVY thereforechange from 4 to 5. In this case the sleeve 24 will have carried thetens `wheel 25r to `a `position where the ligure 4 is, withinone halfVunit of the Areadpoint, and thefjusti-fying mechanism will then be.required to move the wheel 25 forward 10-1 units of movementto .bringtheV tens iigure into position at :the reading point.

The arrangement of the mechanism forY this purpose iis as follows:,(,see' Figs. 2. V4, and 5) vOn one side of numeral bearing wheel 25 isafratchet wheel -26,liavi.ng one tooth for each figure on wheel 25. Onthe other side f wheel 25 is Athe transfer gear 27 already described andthe stepped wheel f 28 whose function will be described late-r.

These wheels 25, 26,27, and 28 are rigidly fastened together by rivets30. V Thecentral portion of the Wheel ,'25 is cut out `forming aVcircular opening' 25A whichcontainsspiral spring 31 attached at one endto-piu 32 which ,is carried by wheel 26 and `at the Y otheryend to anarm33 projecting from sleeve 24. This spring normally pulls wheel 25 ina `counter-clockwise direction so that pin 34 fastened thereto is heldagainst the arm 33 as shown in Fig. 4. The motion of wheel 25 againstthe tension `of spring 3l is limited by pin'3'5. VThis pin 35fis a meresafeguard and has Yno function in the normal operation of thelmechanism.

The necessary forward movement is imparted to thetens wheel 25 by meansof .the ratchet 26 attached theretdand the justifying pawl 86 mounted onVa studS? inthe arm 85. f( See Fig. 5). This arm is .arranged to .rockonfa fix-ed center,84and each ltime a reading is to be taken itisyrocked tothe fixedeposition shownA When'in this position it holdstheratchet .26.in such a 4positi@lathet ,oneofltlie-igures onwheel .it thejustifying pawl,

25 .is in `position at ,the reading point, .the spiral spring 3l holdingone ofthe teeth in ratchet 26 against the pawl. l

kIn the typical example just cited it will be seen that, when theactualV value of the units figure is less than 9iand the' Vvernier p'awl42 representing 9 units controls'V the unit indication, the forwardmovement imparted to the ratchet 26 by justifying pawl 86 should be butslightly more than one half unit and therefore the pawl 86 shouldnotfall behind that tooth on the ratchet lwhich would cause it `to bringtheV figure'l 5 Yon tens wheel25 to the reading point. )Vhen the actualvalue of the units figure is 933 units or over andthejzero vernier pawl42 begins to pact, the justifying pawl Sishould fall behind that toothon ratchet 26 which will cause Yit to bring theiignre 5 on tens wheel 25to the reading point.

As the justifying pawl 36 is mountedon a movable centerjSTiit would bealmost im.- Yposible to canse it to drop behind the tooth representing 5tens at the exact'time that Vthe zero vernicr pawl-42 begins to controlthe reading in place of the nine pawl. To better control the point wherethe pawl ,S6 begins to engage each succeeding ytooth on ratchet 26 weAprovidea pilot pawlSl (sec alsoV F ig. 6)' mounted 0n a liXed center30, which -pawl also Vcooperates withv ratchet 26. VWhen justifyingpawl86 is moved upward to its normal position, shownin Fig. 4, it rides upoverthe pilot. pawl 8l, and at the topof its motiontarm strikesprojection S3 on the pilot pawl ,rocking-it, 'and with out of engagementwith ratchet. 26. Vhen justifying pawl 86 in moved downwardV preparatoryto 'taking reading it ridesV downward over lthe pilot pawl 81 and isthereby piloted behind or overone of the teeth on ratchet 2G accordingto whether or. notthe pilot pawl has dropped behind the tooth.

By extremely accurate workmanship it might be ypossible to cause thepilotV pawl to drop behind the tooth representing tens referring toYthe, example cited) at the exact pointiwhere theV zero Vernier pawl 42begins to control the unit reading in place of the nine pawl.lf'theworkmanship were not suiiiciently accurate the pilot pawl mightdrop, and piloti'the justifying pawl, behind the tooth while the readingremained 9, giving a reading of 59 where it should be 49. Ifv itI failedto drop, and pilot the justifying pawl, behind the tooth when the zerovernierpawl 42-begins to control the unit reading, ,it .would cause areading of 40 where it should be 50.

Toprevent such errors and eliminate the necessity for extremely accurateworkmanship, we provide :means whereby the pilot pawl .is controlledbythe 'same one of 7the Vernier pawls 7425. .which Ycontrols .the` ,unit

ion

lllf) reading. Tov do this we cut the pilot pawl slightly shorter thanit theoretically should be andfthus make it certain to drop behind thattooth on ratchet 26 behind which it should pilot the justifying pawl. Toprevent the pilotpawl from dropping behind the tooth prematurely Wecause the units wheel to operate to position before the justifyingoperation begins,V and. provide a block '64 attached to the units wheel62 in such a position that when the nine Vernier pawl 42 has arrestedthe units wheel ina position representing nine units the block 64is inthe path of the foot 82 on the pilot pawl l8l, (see Figs. 2, 5, and 6.)and prevents it from dropping behind the tooth eventhough it no `longerrests on the point of the tooth, as may be seen in Fig. 5. When the unitreading changes from 9 to 0 the tens reading should also change, andthis change it caused at this time by thefact that when the zero Vernierpawl 42 has arrested theunits wheel in a position representing zerounits, the blockr` 64 is not under the foot 82 on pilot pawl 8l and doesnot preventy itfrom dropping, and piloting the justifying pawl, behindthe next tooth in ratchet26.. 4Thus, inthe example' cited,

when the zero .Vernier pawl 42 begins to control the unit reading thepawl 81 pilots the justifying pawl 86 behind the 5 tooth on ratchetwheel 26 and the pawl 86 turns the wheel 25 forward, against the tensionof spring 31, to a position indicating 5 tens.

If the unitsof measurementwere made much smaller by greatly increasingthe number. of notches in the disk 2() it might be necessary to extendblockv 64'so it would function, not onlyfwhen vwheel 62 is inv aposition representing nine units, but also 8 andperhapseven 7 6, and 5as well, in order to 'make extremev accuracy of workmanship unnecessary;

Thus it is that, through its control of the position of units wheel 62,the Vernier pawl 42 which controls the 'unit reading-also controls thefigures of higher denomination, because the unit value represented bythat pawl determines whether'the' block 64 causes pawl v81 to pilot pawl86 into one tooth or allows it to drop into the, succeeding tooth. "Thestepped wheels 63, 28, and 72 are attached to the sides of the unitswheel 62, the ytens wheel 25, and .the hundreds wheel 70, respectively,r,These are for the purpose of transferring the readingto othermechanism ysuch as large indicators`,"a totalizerv or the like. Themechanism for this ypurpose doesnot form a part 'of the presentinvention andfis not shown infthis case, but one form is shown in ourapplication Serial No. 41,667, filed` 'July24, 1915.

Likewise the mechanism for operating the ring`50' which controls theVernier pawls 42, the arm which controls thejust'fying Van arc; it maybecompressed "as in mechanism, andthe units wheel 62, as well as that formoving the disk 26 and sleeve 24, donot form a part of the p esentinvention and are not here shown.

From the analogyV with ordinary vernier it is apparent that our deviceis as elastic and as adaptable to various usesunder Various conditionsand in Various arrangements as is the Vernier itself. example.: lll/Tehavo seen that it may be straight or curved and may occupy a fnll circlecr only Figs. 'i' and 8 or it may be extended so that spaces betweenpawls are equal to many times the space between'adjacent notches inaddition to the usual Vernier spacing. t live lhave already referred tothe fact that the spacing of a direct or retrograde Vernier may be used,and that the Vernier spacing may or may not be uniform.V The pawls mayalso be spaced to represent the units in any order desired as well asthe natural order 'illustrated in the drawings. It is also evident thatvthe series of pawls may begin with the one pawl as in'Fig. 7 or the zeropawl as in Fig. 8 or with any other unit. It is easily seen that theunits of movement need not be in the decimal system, as commonfractions, English monetary units, degrees and minutes of arc, hours andminutes of time, or any other systemof units can be used by rproperlyspacing the pawls and notches. Although we have regar-dedthe notchedmember as the movable member it is quite evident that it could be'stationary and the pawl carrying membermovable, or both might bemovable, as might. be desired in any particular case. VAlthough we haveshown notches spaced like graduations on scale and pawls spacedvlikegraduations on a Vernier it is quite possible to reverse thatarrangement. Such a reversal might be of advantage on some adaptationsof our invention. It is also evident that the pawls may rock or slide inany manner and be of any form and be actuated by any means suitable tothe particular adaptation contemplated. It is not even necessaryy thatpawls and notches be used as equivalent elements may be substituted.

We have only mentioned a fev.'v of the possible Variations in structureand appli cation of our invention. Many other modifications might bemade by thoseskilled in the art Within the scope of the appended claims.

What we claim is as follows: y

1. A mechanical Vernier comprising in combination, two relativelymovable members, cooperating Vernier means controlled by the relative`position of said members, and indication-producing means controlled byvsaid Vernier' means( y y 2. A mechanical Vernier comprising incombination, two relatively movable mem? bers whose relative position isto .be determined, cooperating VVernier means controlled by the relativeposition of said members, an indicia-bearing device controlled byrelativeV displacement of said members, and a second indicia-bearingdevice controlled by said Vernier means. Y

3. A mechanical Vernier comprising in combination, two relativelymovable meinbers whose relative position is to be determined,cooperating Vernier means controlled by the relative position of saidmembers, and a number-wheel controlled by said Vernier Vmeans.

4. A mechanical Vernier comprising in,

combination, two relatively movable members, cooperating Vernier meansVcontrolled by the relative position of said members, a number-wheelcontrolled by relative Ydisf placement of said members, and a secondtrolled bythe relative'position of said members,V and means controlledby said Vernier means for producing an indication of the relative.displacement of said members.

7 In combination: two relatively movable members; one carrying .a seriesof' notches and the other carrying a series of pawls, which are adaptedto enter saidV notches; and means or determining the relative posi-Vtion of said members, said means being controlledby'one of said pawlswhich has entered a notch. Y f

8. In combination: two relativelyv movable members; and means formechanically measuring their relative movement, comprising:- a series ofnotches carried by one, a series of pawls carriedV by the other, meansfor causing vpawls to enter notches vwith which they register, andmeansfor determining which pawl has entered a notch. Y

9. In combination: two relatively movable members; a series of notches,spaced like uniform graduations on a scale, carried by one; a series ofpawls, spaced like graduations on a Vernier, carried by the other; andmeans for causing pawls to enternotches with which they register.

10. In combination: two relativelyV movable members; a series ofnotches, spaced llike nniforingraduaticns on a scale, carri-ed by one;alseries of `pawlsspaced likegg-radiia.:l

tions lona .ver-nier, carredfby Ythe other; means for, causing pawls to.enter notches with which theyV register; and Vmeans for determiningwhich pawl hasentered a notch.

11. In a computing device: a mechanical Vernier, comprising a memberhaving a series of notches corresponding to graduations, on a scale, amember carrying a series of pawls corresponding to graduations ony aVernier, saidmembers being so associated thatone or another of the pawlsmay enter a notch according `to the relative positions ofthe members.

12. In a mechanical Vernier: two relatively movable members, the firstcarrying a serieszof notches, the second carrying a series `of pawls;means'for causing pawls to enter notches with which they register;mechanism fordetermining units and {igures of higher denomination 1inthe` reading, controlled by -a pawl which has entered a notch.

13.` A mechanical Vernier, comprising: -a member Icarrying a series ofuniformlyy spaced notches; a member-carrying a series of Vernierpawls'adapted to Venter notches .with which ,they register; meansfordetermining the units `figure in thereading, vcontrolled by a pawlfwhichhas ventered a notch; means whereby Vthe ,aforesaid .mechanism maycontrol the vligures .of higherdenomination in the' reading. f Y

14. A mechanical-Vernier, comprising: two relatively movable members,one member carrying a series of uniformly y spaced notches, the othermember carrying a series of pawls, so spaced that each unit of relativemovement between the two members will makeanother pawl register with anotch; and A,mechanism for vdetermining which pawl. registers with lanotch.

15. A `mechanical Vernier, comprising: a member carrying a seriesofnotches; another member carrying aY seriesopawls representing units,so :spaced that the` pawl which represents .the `unit-s @figure Yinthereading will register with a notch;.and mechanism, for determining.which pawl registers with a notch 1 v 16. Ina mechanicalA Vernier: tworelatively movable members, one f member carrying a series of notches.corresponding. to gra-du ations von a .sca-le: the other membercarryinga series .of pawls corresponding to graduations on avernier; 'andmechanism .fordetermining whichV .pawl Irepresents the Vfigure nearestto the..oori.ect reading.

17.l In Ha mechanical Vernier: member; another member. carrying a seriesof pawls representing units, so arranged thatthe pawlrepresenting theunits gure inthe reading vwill .drop into fanotch v means forcontrolling the point-ofgtransition between two .consecutive readingsVby. `allowing two pawls .tOsimUltaneously occupy notcheson.mandala@aangegaanpoint a notchedV 18. In a mechanical. Vernier: anotched member; another member carrying a series of pawls representingunits, so arranged that the pawl representing the units ligure in thereading will drop into a notch; means for allowing two pawls tosimultaneously. occupy notches when the reading is half way between twounits; and means for causing the pawl representing the higher value tocontrol the reading in that case.

19. In a mechanical Vernier: two relatively movable members, one membercarrying a series of notches, the other member carrying a series ofVernier pawls so arranged that the one representing the units figure inthe reading is adapted to enter a notch; and reading mechanismcontrolled by a pawl which has entered a notch.

20. In a mechanical Vernier: two relatively movable members, one membercarrying a series of notches, the other member carrying a series ofVernier pawls so arranged that the pawl representing the units figure inthe reading is adapted to enter a notch; reading mechanism controlled bya pawl which has entered a notch; means for causing two pawls tosimultaneously occupy notches When the exact reading is midway betweentwo units; and means for causing the pawl representing the higher valueto control the reading mechanism in that case.

21. In a mechanical Vernier: two relatively movable members; a series ofnotches on the one; a series of pawls, representing units in thereading, on the other; means for causing a pawl to enter a notch; meansfor causing two pawls to enter notches when the reading is midwaybetween two units; a member adapted to pass the unit pawls in descendingsequence and be arrested by a pawl which has entered a notch; and meansfor preventing one of two particular pawls in the series from entering anotch, when from the relative position of said members, both pawls mightenter notches.

22. In a measuring device: a rotatable notched disk; pawls mountedcontiguous thereto; and means for measuring the rotation of the disk,comprising mechanism for determining the units figure in themeasurement, controlled by a pawl which registers with a notch. r

23. In a measuring device: a rotatable notched disk; a series of pawlsmounted contiguous thereto; means for measuring the rotation of thedisk, comprising: a movable member, for determining the units figure inthe measurement, controlled by a pawl in the series which registers witha notch; mechanism for determining the iigures of higher denomination;and means whereby the pawl which controls said member also controls saidmechanism.

24. A mechanical Vernier, comprising: a rotatable notched disk; a seriesof pawls mounted contiguous thereto; means for determining the unitsfigure in the reading, comprising means for causing pawls to enternotches which register therewith, and a movable member controlled by apawl which has entered a notch.

25. A mechanical Vernier, comprising: a rotatable notched disk; a seriesof pawls mounted contiguous thereto; means for determining the unitsfigure in the reading, comprising means for causing pawls to enternotches which register therewith, means for causing two pawls to occupynotches simultaneously at the point of transition between twoconsecutive unit readings, and a movable member controlled by a pawlwhich has entered a notch.

26. A mechanical Vernier, comprising: a rotatable notched disk; a seriesof pawls mounted contiguous thereto; means for determining the unitsligure in the reading, comprising means for causing pawls to enternotches which register therewith, means for causing two pawls to occupynotches simultaneously at the point of transition between twoconsecutive unit readings, a movable member controlled by a pawl whichhas entered a notch, and means for causing the proper one of these twopawls to control said member.

27. A mechanical Vernier, comprising: a rotatable notched disk; a seriesof pawls mounted contiguous thereto; means for determining the unitsfigure in the reading, comprising means for causing pawls to enternotches which register therewith, means for causing two pawls to occupynotches simultaneously at the point of transition between twoconsecutive unit readings, a movable member controlled by a pawl whichhas entered a notch, and means for causing the proper one of these twopawls to control said member, including means for preventing the twopawls adjacent to the normal position of said member from occupyingnotches simultaneously.

EDITH E. L. BOYER. FREDERICK G. L. BOYER.

